Betulin is a pentacyclic triterpenoid derived from the outer bark of paper birch trees (Betula paperifera). It can be present at concentrations of up to about 24% of the bark of white birch. Merck Index, twelfth edition, page 1236, 1996. Lupeol is a related compound also found in birch bark and in other plant sources. Lupeol is present at concentrations of about 1.5-3% of birch bark and at up to about 8.2% in Canavalia ensiformis, a plant widespread in the humid tropics of Asia, India, and Africa. Allobetulin is another triterpenoid found in birch bark. A typical pulp mill that processes birch produces enough bark waste to allow for the inexpensive isolation of significant quantities of these triterpenoids.
Several triterpenoids have been found to have utility. For example, betulin and related compounds have been shown to have anti-viral activity against herpes simplex virus. Carlson et al., U.S. Pat. No. 5,750,578.
Bacteria are very common pathogens of humans. Among the bacterial species that cause serious disease are the gram negative bacterium Escherichia coli and gram positive bacteria of the genus Staphylococcus. Staphylococcus aureus is the most serious pathogen of the Staphylococcus bacteria, It is estimated to causes 13% of the 2 million hospital infections each year, and result in 80,000 deaths in the United States. Staphylococcal infections occur most commonly in persons weakened by poor health or immunodeficiency.
Antibiotic resistance of bacteria is a growing problem. New agents active against bacteria are needed. A need particularly exists for agents that will act against a range of species, including gram-negative and gram-positive species. Ideally, new agents would also be inexpensive to manufacture. New anti-bacterial agents would be less expensive to manufacture if they were abundant natural products or were easily synthesized from abundant natural products.
The present invention provides a therapeutic method of treating a mammal afflicted with a bacterial infection, the method comprising administering to the mammal an effective antibacterial amount of a triterpene of formula (I): 
wherein
R1 is hydrogen or hydroxy;
R2 is a direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl;
R3 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94,(C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, or a glycoside;
R4 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94, (C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, a glycoside, or amino; or R4 and R5 together are oxo or (xe2x95x90NOH); and
R5 is direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl; or R4 and R, together are oxo or (xe2x95x90NOH);
wherein any alkyl can optionally be substituted with one or more halo, hydroxy, (C6-C10)aryl, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; xe2x80x94OP(xe2x95x90O)(OH)2; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
each of the bonds represented byxe2x80x94is independently absent or is present;
wherein any alkyl is optionally interrupted on carbon with one or more oxy, thio, sulfinyl, sulfonyl, polyethyleneimine, or poly(ethylene glycol);
wherein any alkyl is optionally partially unsaturated;
wherein any aryl can optionally be substituted with one or more halo, hydroxy, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
or a pharmaceutically acceptable salt thereof.
The present invention also provides a therapeutic method of treating a mammal afflicted with a bacterial infection, the method comprising administering to the mammal an effective antibacterial amount of a triterpene of formula (II): 
wherein
one of R1 and R2 is xe2x80x94Oxe2x80x94Y and the other is hydrogen or (C1-C6)alkyl optionally substituted by hydroxy, (C1-C6)alkoxy, halo, halo(C1-C6)alkoxy or NRjRk wherein Rj and Rk are independently H, (C1-C6)alkyl or (C1-C6)alkanoyl; or R1 and R2 together are oxo (xe2x95x90O);
R3 is hydrogen, halo, carboxy, mercapto, (C1-C6)alkyl, (C3-C8)cycloalkyl, or xe2x80x94oxe2x80x94Y;
R4 and R5 are each independently hydrogen, (C1-C6)alkyl, or hydroxy(C1-C6)alkyl;
R6 is hydrogen or is absent when the adjacentxe2x80x94is a bond;
R7 is hydrogen or (C1-C6)alkyl;
R8 is hydrogen, (C1-C6)alkyl, or hydroxy(C1-C6)alkyl and R11 is hydrogen, (C1-C6)alkyl carboxy, or hydroxy(C1-C6)alkyl; or R8 and R11 together are xe2x80x94Oxe2x80x94C(xe2x95x90X)xe2x80x94;
R9 and R10, are each independently hydrogen or (C1-C6)alkyl;
each of the bonds represented byxe2x80x94is independently absent or is present;
X is two hydrogens, oxo (xe2x95x90O) or thioxo (xe2x95x90S);
each Y is independently H, aryl, P(O)(Cl)2, (C3-C8)cycloalkyl, adamantyl, xe2x80x94SO2Ra Oxe2x95x90P(Rb)2, Oxe2x95x90P(Rc)2OP(O)(Rd)xe2x80x94, Si(Re)3, tetrahydropyran-2-yl, an amino acid, a peptide, a glycoside, or a 1 to 10 membered branched or unbranched carbon chain optionally comprising 1, 2, or 3 heteroatoms selected from non-peroxide oxy, thio, and xe2x80x94N(Rf)xe2x80x94; wherein said chain may optionally be substituted on carbon with 1, 2, 3, or 4 oxo (xe2x95x90O), hydroxy, carboxy, halo, mercapto, nitro, xe2x80x94N(Rg)(Rh), (C3-C8)cycloalkyl, (C3-C8)cycloalkyloxy, aryl, aryloxy, adamantyl, adamantyloxy, hydroxyamino, trifluoroacetylamino, a glycoside, an amino acid, or a peptide; and wherein said chain may optionally be saturated or unsaturated (e.g. containing one, two, three or more, double or triple bonds);
Ra is (C1-C6)alkyl or aryl;
Rb, Rc, and Rd are each independently hydroxy, (C1-C6)alkoxy, hydroxy(C2-C6)alkoxy, adamantyloxy, adamantyl(C1-C6)alkoxy, norbomyloxy, 1,1-di(hydroxymethyl)-2-hydroxyethoxy, carboxy(C1-C6)alkoxy, 2,3-epoxypropyloxy, benzyloxy, (C3-C8)cycloalkyloxy, NRxRy, or aryloxy;
Re is H, aryl or (C1-C6)alkyl;
Rf is hydrogen, (C1-C6)alkyl, (C1-C6)alkanoyl, phenyl or benzyl;
Rg and Rh are each independently selected from the group consisting of hydrogen, (C1-C6)alkyl, hydroxy(C1-C6)alkyl, adamantyl, adamantyl(C1-C6)alkyl, amino(C1-C6)alkyl, aminosulfonyl, (C1-C6)alkanoyl, aryl and benzyl; or Rb and Rc together with the nitrogen to which they are attached form a pyrrolidino, piperidino, or morpholino radical; and
Rx and Ry are each independently hydrogen, (C1-C6)alkyl, (C1-C6)alkanoyl, aryl or benzyl;
wherein each aryl of Y, Raxe2x80x94Rd, Rgxe2x80x94Rh, Rx, and Ry may optionally be substituted by 1, 2, or 3 aminosulfonyl, carboxy, NRiRj, (C1-C6)alkyl, (C1-C6)alkoxy, hydroxy, halo, nitro, cyano, mercapto, carboxy, hydroxy(C1-C6)alkyl, halo(C1-C6)alkyl, trifluoromethoxy, (C1-C6)alkanoyl, (C1-C6)alkoxycarbonyl, (C1-C6)alkylthio, or (C1-C6)alkanoyloxy; wherein Ri and Rj are each independently hydrogen, (C1-C6)alkyl, (C1-C6)alkanoyl, phenyl, or benzyl;
wherein any alkyl can optionally be substituted with one or more polyethyleneimine or poly(ethylene glycol); and wherein any alkyl can optionally be interrupted with one or more polyethyleneimine or poly(ethylene glycol);
or a pharmaceutically acceptable salt thereof.
The present invention also provides a method of inhibiting or killing a bacterium, the method comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (I): 
wherein
R1 is hydrogen or hydroxy;
R2 is a direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl;
R3 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94, (C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, or a glycoside;
R4 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94, (C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, a glycoside, or amino; or R4 and R5 together are oxo or (xe2x95x90NOH); and
R5 is direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl; or R4 and R5 together are oxo or (xe2x95x90NOH);
wherein any alkyl can optionally be substituted with one or more halo, hydroxy, (C6-C10)aryl, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; xe2x80x94OP(xe2x95x90O)(OH)2; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
each of the bonds represented byxe2x80x94is independently absent or is present;
wherein any alkyl is optionally interrupted on carbon with one or more oxy, thio, sulfinyl, sulfonyl, polyethyleneimine, or poly(ethylene glycol);
wherein any alkyl is optionally partially unsaturated;
wherein any aryl can optionally be substituted with one or more halo, hydroxy, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
or a pharmaceutically acceptable salt thereof.
The present invention also provides a method of inhibiting or killing a bacterium, the method comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (II): 
wherein
one of R1 and R2 is xe2x80x94Oxe2x80x94Y and the other is hydrogen or (C1-C6)alkyl optionally substituted by hydroxy, (C1-C6)alkoxy, halo, halo(C1-C6)alkoxy or NRjRk wherein Rj and Rk are independently H, (C1-C6)alkyl or (C1-C6)alkanoyl; or R1 and R2 together are oxo (xe2x95x90O);
R3 is hydrogen, halo, carboxy, mercapto, (C1-C6)alkyl, (C3-C8)cycloalkyl, or xe2x80x94Oxe2x80x94Y;
R4 and R5 are each independently hydrogen, (C1-C6)alkyl, or hydroxy(C1-C6)alkyl;
R6 is hydrogen or is absent when the adjacentxe2x80x94is a bond;
R7 is hydrogen or (C1-C6)alkyl;
R8 is hydrogen, (C1-C6)alkyl or hydroxy(C1-C6)alkyl and R11 is hydrogen, (C1-C6)alkyl, carboxy, or hydroxy(C1-C6)alkyl; or R8 and R11 together are xe2x80x94Oxe2x80x94C(xe2x95x90X)xe2x80x94;
R9 and R10, are each independently hydrogen or (C1-C6)alkyl;
each of the bonds represented byxe2x80x94is independently absent or is present;
X is two hydrogens, oxo (xe2x95x90O) or thioxo (xe2x95x90S);
each Y is independently H, aryl, P(O)(Cl)2, (C3-C8)cycloalkyl, adamantyl, xe2x80x94SO2Ra Oxe2x95x90P(Rb)2, Oxe2x95x90P(Rc)2OP(O)(Rd)xe2x80x94, Si(Re)3, tetrahydropyran-2-yl, an amino acid, a peptide, a glycoside, or a 1 to 10 membered branched or unbranched carbon chain optionally comprising 1, 2, or 3 heteroatoms selected from non-peroxide oxy, thio, and xe2x80x94N(Rf)xe2x80x94; wherein said chain may optionally be substituted on carbon with 1, 2, 3, or 4 oxo (xe2x95x90O), hydroxy, carboxy, halo, mercapto, nitro, xe2x80x94N(Rg)(Rh), (C3-C8)cycloalkyl, (C3-C8)cycloalkyloxy, aryl, aryloxy, adamantyl, adamantyloxy, hydroxyamino, trifluoroacetylamino, a glycoside, an amino acid, or a peptide; and
wherein said chain may optionally be saturated or unsaturated (e.g. containing one, two, three or more, double or triple bonds);
Ra is (C1-C6)alkyl or aryl;
Rb, Rc, and Rd are each independently hydroxy, (C1-C6)alkoxy, hydroxy(C2-C6)alkoxy, adamantyloxy, adamantyl(C1-C6)alkoxy, norbornyloxy, 1,1-di(hydroxymethyl)-2-hydroxyethoxy, carboxy(C1-C6)alkoxy, 2,3-epoxypropyloxy, benzyloxy, (C3-C8)cycloalkyloxy, NRxRy, or aryloxy;
Re is H, aryl or (C1-C6)alkyl;
Rf is hydrogen, (C1-C6)alkyl, (C1-C6)alkanoyl, phenyl or benzyl;
Rg and Rh are each independently selected from the group consisting of hydrogen, (C1-C6)alkyl, hydroxy(C1-C6)alkyl, adamantyl, adamantyl(C1-C6)alkyl, amino(C1-C6)alkyl, aminosulfonyl, (C1-C6)alkanoyl, aryl and benzyl; or Rb and Rc together with the nitrogen to which they are attached form a pyrrolidino, piperidino, or morpholino radical; and
Rx and Ry are each independently hydrogen, (C1-C6)alkyl, (C1-C6)alkanoyl, aryl or benzyl;
wherein each aryl of Y, Raxe2x80x94Rd, Rgxe2x80x94Rh, Rx, and Ry may optionally be substituted by 1, 2, or 3 aminosulfonyl, carboxy, NRiRj, (C1-C6)alkyl, (C1-C6)alkoxy, hydroxy, halo, nitro, cyano, mercapto, carboxy, hydroxy(C1-C6)alkyl, halo(C1-C6)alkyl, trifluoromethoxy, (C1-C6)alkanoyl, (C1-C6)alkoxycarbonyl, (C1-C6)alkylthio, or (C1-C6)alkanoyloxy; wherein Ri and Rj are each independently hydrogen, (C1-C6)alkyl, (C1-C6)alkanoyl, phenyl, or benzyl;
wherein any alkyl can optionally be substituted with one or more polyethyleneimine or poly(ethylene glycol); and wherein any alkyl can optionally be interrupted with one or more polyethyleneimine or poly(ethylene glycol);
or a pharmaceutically acceptable salt thereof.
The present invention provides a therapeutic method of treating a mammal afflicted with a bacterial infection, the method comprising administering to the mammal an effective antibacterial amount of a triterpene of formula (I): 
wherein
R1 is hydrogen or hydroxy;
R2 is a direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl;
R3 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94, (C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, or a glycoside;
R4 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94, (C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, or a glycoside; or R4 and R5 together are oxo; and
R5 is direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl; or R4 and R5 together are oxo;
wherein any alkyl can optionally be substituted with one or more halo, hydroxy, (C6-C10)aryl, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; xe2x80x94OP(xe2x95x90O)(OH)2; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
each of the bonds represented byxe2x80x94is independently absent or is present;
wherein any alkyl is optionally interrupted on carbon with one or more oxy, thio, sulfinyl, sulfonyl, polyethyleneimine, or poly(ethylene glycol);
wherein any alkyl is optionally partially unsaturated;
wherein any aryl can optionally be substituted with one or more halo, hydroxy, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
or a pharmaceutically acceptable salt thereof.
The present invention also provides a method of inhibiting or killing a bacterium, the method comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (I): 
wherein
R1 is hydrogen or hydroxy;
R2 is a direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl;
R3 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94, (C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, or a glycoside;
R4 is hydrogen, hydroxy, (C1-C6)alkyl, Oxe2x95x90P(OH)2, Oxe2x95x90P(OH)2OP(O)(OH)xe2x80x94, (C1-C5)alkanoyl, Si(R)3 wherein each R is H, phenyl or (C1-C6)alkyl, C(O)N(R)2, benzyl, benzoyl, tetrahydropyran-2-yl, 1-[(C1-C4)alkoxy](C1-C4)alkyl, or a glycoside; or R4 and R5 together are oxo; and
R5 is direct bond, carbonyl, oxy, thio, carbonyl oxy, oxy carbonyl, (C6-C10)aryl, or (C1-C6)alkyl; or R4 and R5 together are oxo;
wherein any alkyl can optionally be substituted with one or more halo, hydroxy, (C6-C10)aryl, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; xe2x80x94OP(xe2x95x90O)(OH)2; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
each of the bonds represented byxe2x80x94is independently absent or is present;
wherein any alkyl is optionally interrupted on carbon with one or more oxy, thio, sulfinyl, sulfonyl, polyethyleneimine, or poly(ethylene glycol);
wherein any alkyl is optionally partially unsaturated;
wherein any aryl can optionally be substituted with one or more halo, hydroxy, nitro, cyano, (C1-C6)alkoxy, trifluoromethyl, polyethyleneimine, poly(ethylene glycol), oxo, NR7R8, wherein R7 and R8 are each independently hydrogen, (C1-C6)alkyl or polyethyleneimine; or C(xe2x95x90O)OR9, wherein R9 is hydrogen, (C1-C6)alkyl, or polyethyleneimine;
or a pharmaceutically acceptable salt thereof.
The invention provides novel compounds of formula (I) and formula (II), intermediates for the synthesis of compounds of formula (I) and formula (II), as well as methods of preparing compounds of formula (I) and (II). The invention also provides compounds of formula (I) and (II) that are useful as intermediates for the synthesis of other useful compounds. The invention provides for the use of compounds of formula (I) and formula (II) for the manufacture of medicaments useful for the treatment of bacterial infections in a mammal, such as a human.
The following definitions are used, unless otherwise described: halo is fluoro, chloro, bromo, or iodo. Alkyl, alkoxy, alkenyl, etc. denote both straight and branched groups; but reference to an individual radical such as xe2x80x9cpropylxe2x80x9d embraces only the straight chain radical, a branched chain isomer such as xe2x80x9cisopropylxe2x80x9d being specifically referred to. Aryl denotes a phenyl radical or an ortho-fused bicyclic carbocyclic radical having about nine to ten ring atoms in which at least one ring is aromatic.
It will be appreciated by those skilled in the art that compounds useful in the invention having a chiral center may exist in and be isolated in optically active and racemic forms. Some compounds may exhibit polymorphism. It is to be understood that the present invention encompasses any racemic, optically-active, polymorphic, or stereoisomeric form, or mixtures thereof, of a compound useful in the invention, which possess the useful properties described herein, it being well known in the art how to prepare optically active forms (for example, by resolution of the racemic form by recrystallization techniques, by synthesis from optically-active starting materials, by chiral synthesis, or by chromatographic separation using a chiral stationary phase) and how to determine antibacterial activity using the standard tests described herein, or using other similar tests which are well known in the art.
Specific and preferred values listed below for radicals, substituents, and ranges, are for illustration only; they do not exclude other defined values or other values within defined ranges for the radicals and substituents.
Specifically, (C1-C6)alkyl can be methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, sec-butyl, pentyl, 3-pentyl, or hexyl; partially unsaturated (C2-C6)alkyl or (C2-C6)alkenyl can be vinyl, 1-propenyl, 2-propenyl, 1-butenyl, 2-butenyl, 3-butenyl, 1,-pentenyl, 2-pentenyl, 3-pentenyl, 4-pentenyl, 1-hexenyl, 2-hexenyl, 3-hexenyl, 4-hexenyl, or 5-hexenyl; (C1-C5)alkanoyl can be carbonyl, acetyl, propanoyl, butanoyl, isopropanoyl, or pentenoyl; (C1-C6)alkoxy can be methoxy, ethoxy, propoxy, isopropoxy, butoxy, iso-butoxy, sec-butoxy, pentoxy, 2-pentoxy, 3-pentoxy, or hexyloxy; halo(C1-C6)alkoxy can be trifluoromethyloxy, 2-chloroethyloxy, 3,3-dichloropropyloxy, or 4,4,4-trifluorobutyloxy; (C3-C8)cycloalkyl can be cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, or cyclooctyl; (C3-C8)cycloalkyloxy can be cyclopropyloxy, cyclobutyloxy, cyclopentyloxy, cyclohexyloxy, cycloheptyloxy, or cyclooctyloxy; hydroxy(C1-C6)alkoxy can be hydroxymethoxy, 1-hydroxyethoxy, 2-hydroxyethoxy, 1-hydroxypropoxy, 2-hydroxypropoxy, 3-hydroxypropoxy, 1-hydroxybutoxy, 4-hydroxybutoxy, 1-hydroxypentoxy, 5-hydroxypentoxy, 1-hydroxyhexoxy, or 6-hydroxyhexoxy; amino(C1-C6)alkyl can be aminomethyl, 1-aminoethyl, 2-aminoethyl, 1-aminopropyl, 2-aminopropyl, 3-aminopropyl, 1-aminobutyl, 2-aminobutyl, 3-aminobutyl, 4-aminobutyl, 1-aminopentyl, 2-aminopentyl, 3-aminopentyl, 5-aminopentyl, 1-aminohexyl, 2-aminohexyl, 3-aminohexyl, or 6-aminohexyl; (C1-C6)alkoxycarbonyl can be methoxycarbonyl, ethoxycarbonyl, propyloxycarbonyl, isopropyloxycarbonyl, 2-methylpropyloxycarbonyl, butyloxycarbonyl, pentyloxycarbonyl, or hexyloxycarbonyl; (C1-C6)alkanoyloxy can be carbonyloxy, acetyloxy, propanoyloxy, butanoyloxy, 2-methylpropanoyloxy, 2-methylbutanoyloxy, 3-methylbutanoyloxy, pentanoyloxy, or hexanoyloxy.
xe2x80x9c3-carboxypropenoyloxymethylxe2x80x9d refers to the group xe2x80x94CH2OC(xe2x95x90O)CHxe2x95x90CHCOOH;
xe2x80x9caminoacetoxymethylxe2x80x9d refers to the group xe2x80x94CH2OC(xe2x95x90O)CH2NH2;
xe2x80x9c(carboxymethoxy)acetoxymethylxe2x80x9d refers to the group xe2x80x94CH2OC(xe2x95x90O)CH2OCH2COOH;
xe2x80x9c4-carboxybutanoyloxymnethylxe2x80x9d refers to the group xe2x80x94CH2OC(xe2x95x90O)CH2CH2CH2COOH;
xe2x80x9c2-carboxybenzoyloxymethylxe2x80x9d refers to the group 
xe2x80x9cbutanoyloxymethylxe2x80x9d refers to the group xe2x80x94CH2OC(xe2x95x90O)CH2CH2CH3;
xe2x80x9c2-carboxybenzoylxe2x80x9d refers to the group 
xe2x80x9c2-amino-3-methylbutanoylxe2x80x9d refers to the group xe2x80x94C(xe2x95x90O)CH2(NH2)CH2(CH3)2;
xe2x80x9c3-carboxypropenoylxe2x80x9d refers to the group -C(xe2x95x90O)CHxe2x95x90CHCOOH;
xe2x80x9caminoacetylxe2x80x9d refers to the group xe2x80x94C(xe2x95x90O)CH2NH2;
xe2x80x9c4-carboxybutanoylxe2x80x9d refers to the group xe2x80x94C(xe2x95x90O)CH2CH2CH3COOH,
xe2x80x9c(carboxymethoxy)acetylxe2x80x9d refers to the group xe2x80x94C(xe2x95x90O)CH2OCH2COOH,
xe2x80x9c3-(3,4-dihydroxyphenyl)propenoylxe2x80x9d refers to the group 
xe2x80x9ccarboxymethylenethioacetylxe2x80x9d refers to the group xe2x80x94C(xe2x95x90O)CH2SCH2COOH;
xe2x80x9c3-carboxy-3-methylbutanoylxe2x80x9d refers to the group xe2x80x94C(xe2x95x90O)CH2C(COOH)(CH3)2;
xe2x80x9coximexe2x80x9d refers to the group (xe2x95x90NOH) that is substituted directly on a carbon atom, thereby providing the group Cxe2x95x90Nxe2x80x94OH.
The term xe2x80x9camino acid,xe2x80x9d comprises the residues of the natural amino acids (e.g. Ala, Arg, Asn, Asp, Cys, Glu, Gln, Gly, His, Hyl, Hyp, Ile, Leu, Lys, Met, Phe, Pro, Ser, Thr, Trp, Tyr, and Val) in D or L form, as well as unnatural amino acids (e.g. phosphoserine, phosphothreonine, phosphotyrosine, hydroxyproline, gamma-carboxyglutamate; hippuric acid, octahydroindole-2-carboxylic acid, statine, 1,2,3,4,-tetrahydroisoquinoline-3-carboxylic acid, penicillamine, omithine, citruline, xcex1-methyl-alanine, para-benzoylphenylalanine, phenylglycine, propargylglycine, sarcosine, and tert-butylglycine). The term also comprises natural and unnatural amino acids bearing a conventional amino protecting group (e.g. acetyl or benzyloxycarbonyl), as well as natural and unnatural amino acids protected at the carboxy terminus (e.g. as a (C1-C6)alkyl, phenyl or benzyl ester or amide; or as an xcex1-methylbenzyl amide). Other suitable amino and carboxy protecting groups are known to those skilled in the art (See for example, T. W. Greene, Protecting Groups In Organic Synthesis; Wiley: New York, Third Edition, 1999, and references cited therein). An amino acid can be linked to the remainder of a compound of formula I or II through the carboxy terminus, the amino terminus, or through any other convenient point of attachment, such as, for example, through the sulfur of cysteine.
The term xe2x80x9cpeptidexe2x80x9d describes a sequence of 2 to 25 amino acids (e.g. as defined herein) or peptidyl residues. The sequence may be linear or cyclic. For example, a cyclic peptide can be prepared or may result from the formation of disulfide bridges between two cysteine residues in a sequence. A peptide can be linked to the remainder of a compound of formula I or II through the carboxy terminus, the amino terminus, or through any other convenient point of attachment, such as, for example, through the sulfur of a cysteine. Preferably a peptide comprises 3 to 25, or 5 to 21 amino acids. Peptide derivatives can be prepared as disclosed in U.S. Pat. Nos. 4,612,302; 4,853,371; and 4,684,620.
Glycosides are formed by reacting mono-, di- and polysaccharides with 1-2 hydroxyl groups of the compound of formula (I) or formula (II), including glucose, glucuronic acid, mannose, galactose, sorbase, ribose, maltose, sucrose, modified cellulosics, dextrans, modified starches and the like. These derivatives can advantageously exhibit improved water solubility over betulin itself. See, Remington ""s Pharmaceutical Sciences, A. R. Gennaro, ed., Mack Pub. Co. (18th ed., 1990) at pages 384-386. Glycoside derivatives can be prepared as described in PCT Applications WO 96/34005 and 97/03995.
xe2x80x9cPolyethyleneiminexe2x80x9d refers to the group (xe2x80x94NHCH2CH2xe2x80x94)x[xe2x80x94N(CH2CH2NH2)CH2CH2xe2x80x94]y. Polyethyleneimine can be attached to a compound of formula I or II through either of the nitrogen atoms marked with hash marks. xe2x80x9cPoly(ethylene glycol)xe2x80x9d refers to the compound H(OCH2CH2)nOH. It can be attached to a compound of formula I or II through the terminal hydroxyl group.
The term xe2x80x9cpartially unsaturatedxe2x80x9d refers to a linear or branched hydrocarbon having one or more carbonxe2x80x94carbon double bonds.
The term xe2x80x9cphosphonoxe2x80x9d refers to Oxe2x95x90P(OH)2xe2x80x94.
The term xe2x80x9cdirect bondxe2x80x9d refers to a group being absent.
Combinations of substituents and/or variables are permissible only if such combinations result in stable compounds. By xe2x80x9cstable compoundxe2x80x9d is meant herein a compound that is sufficiently robust to survive isolation to a useful degree of purity from a reaction mixture, and formulation into an efficacious antibacterial agent.
The term xe2x80x9cbacteriumxe2x80x9d or xe2x80x9cbacteriaxe2x80x9d refers to any prokaryotic organism.
The structure and carbon numbering of three exemplary compounds of the present invention are shown below. 
Specific values for compounds of formula (I) are as follows:
A specific value for the bond between carbons 1 and 2 is a single bond.
Another specific value for the bond between carbons 1 and 2 is a double bond.
A specific value for R1 is hydrogen.
Another specific value for R1 is hydroxy.
A specific value for R2 is a direct bond.
A specific value for R3 is(C1-C6)alkyl; wherein any alkyl can optionally be substituted with one or more oxo, carboxy, amino, (C6-C10)aryl, or xe2x80x94OP(xe2x95x90O)(OH)2; any alkyl is optionally interrupted on carbon with one or more oxy or thio; any alkyl is optionally partially unsaturated; and any aryl can optionally be substituted with one or more hydroxy or carboxy.
Another specific value for R3 is 3-carboxypropenoyloxymethyl, aminoacetoxymethyl, (carboxymethoxy)acetoxymethyl, 4-carboxybutanoyloxymethyl, 2-carboxybenzoyloxymethyl, butanoyloxymethyl, or xe2x80x94CH2OC(xe2x95x90O)OP(xe2x95x90O)(OH)2.
A specific value for R4 is (C1-C6)alkyl; wherein any alkyl can optionally be substituted with one or more oxo, carboxy, amino, (C6-C10)aryl, or xe2x80x94OP(xe2x95x90O)(OH)2; any alkyl is optionally interrupted on carbon with one or more oxy or thio; any alkyl is optionally partially unsaturated; and any aryl can optionally be substituted with one or more hydroxy or carboxy.
Another specific value for R4 is 2-carboxybenzoyl, 2-amino-3-methylbutanoyl, 3-carboxypropenoyl, aminoacetyl, 4-carboxybutanoyl, (carboxymethoxy)acetyl, 3-(3,4-dihydroxyphenyl)propenoyl, carboxymethylenethioacetyl, 3-carboxy-3-methylbutanoyl, amino, xe2x80x94P(xe2x95x90O)(OH)2, oxo, or (xe2x95x90NOH).
A specific value for R5 is oxy or a direct bond.
A specific group of compounds are compounds of formula (I) wherein R1 is hydrogen or hydroxy; R2 is a direct bond; R3 is (C1-C5)alkoxymethyl or hydroxymethyl; R4 is hydrogen, phosphono, sulfo, or (C1-C6)alkyl, and R5 is oxy; or R4 is amino and R5 is a direct bond; or R4 and R5 together are oxo or (xe2x95x90NOH); wherein any alkyl, or alkyl segment of an R group, is optionally interrupted on carbon with one or more oxy, thio, or imido; wherein any alkyl, or alkyl segment of an R group, can optionally be substituted with one or more oxo, carboxy, amino, xe2x80x94OP(xe2x95x90O)(OH)2, or phenyl; wherein phenyl can optionally be substituted with one or more hydroxy or carboxy.
Another specific group of compounds are compounds of formula (I) wherein R1 is hydrogen or hydroxy; R2 is a direct bond; R3 is 3-carboxypropenoyloxymethyl, aminoacetoxymethyl, (carboxmethoxy)acetoxymethyl, 4-carboxybutanoyloxymethyl, 2-carboxybenzoyloxymethyl, butanoyloxymethyl, or xe2x80x94CH2OC(xe2x95x90O)OP(xe2x95x90O)(OH)2; R4 is 2-carboxybenzoyl, 2-amino-3-methylbutanoyl, 3-carboxypropenoyl, aminoacetyl, 4-carboxybutanoyl, (carboxymethoxy)acetyl, 3-(3,4-dihydroxyphenyl)propenoyl, carboxymethylenethioacetyl, 3-carboxy-3-methylbutanoyl, amino, xe2x80x94P(xe2x95x90O)(OH)2, oxo, or (xe2x95x90NOH); and R5 is oxy or a direct bond.
Another specific group of compounds of formula (I) is betulin; betulin-3,28-diglycine; betulin-28-glycerol oxalate; betulin-28-glycine; betulin-28-oxalate; betulin arabinose galactan; betulin-3,28-didiglycolate; betulin-3,28-diglycine; betulin-3-maleate; betulin-3,28-di-(L-Glutamic acid r-benzylester) ester; betulin-3,28-di-L-alanine; betulin-3,28-di-L-proline; betulin-3,28-dioxalate; betulin-1-ene-2-ol; betulin-3,28-diphenylalanine; betulin-3-28-dioxalate-polyethylene amine; betulin-3,38-diphosphate; betulin-3-caffeate; betulin-3,28-(3xe2x80x2,3xe2x80x2-dimethyl) glutarate; betulin-28-diglycolate; betulin-28-glutarate; betulin-28-maleate; betulin-28-phthalate; betulin-3,28-di(3xe2x80x2,3xe2x80x2-dimethyl)glutarate; betulin-3,28-didiglycolate; betulin-3,28-di(thiodiglycolate); betulin-3,28-diglutarate; betulin-3,28-dimaleate; betulin-3,28-diglycolate; betulin-3,28-diphthalate; betulin-3,28-di-L-phenylalanine; betulin-3,28-di-L-valine; betulin-28-succinate; betulin-3,28-disuccinate; betulin-3,28-di-(polyethylene glycol)-COOH (Mw=1448); betulin-3,28-di-(polyethylene glycol)-COOH (Mw=906 crude); betulin-3,28-di-(polyethylene glycol)-COOH (Mw=906 pure); betulinic acid; betulon-1-ene-2-ol; betulin-3,28-(dipoly(ethylene glycol)bis (carboxymethylester); allobetulin-3,28-(dipoly(ethylene glycol)bis (carboxymethyl ester); hederin hydrate; lupeol; lupeol-3-glutarate; lupeol-3-succinate; lupeol-3-thiodiglycolate; lupeol-3-phthalate; lupeol-3-succinate; oleanolic acid; ursolic acid; or uvaol.
Another specific group of compounds of formula (I) is betulin; betulin-28-glycerol oxalate; betulin-28-oxalate; betulin arabinose galactan; betulin-3,28-didiglycolate; betulin-3,28-diglycine; betulin-3,28-di-(L-glutamic acid y-benzylester) ester; betulin3,28-di-L-proline ester; betulin-3,28-dioxalate; betulin-1-ene-2-ol; betulin-3,28-dioxalate-polyethylene amine; betulin-3,28-diphosphate; betulin-3-caffeate; betulin-28-diglycolate; betulin-28-glutarate; betulin-28-maleate; betulin-28-phthalate; betulin-3,28-dithiodiglycolate; betulin-3,28-diglutarate; betulin-3,28-dimaleate; betulin-3,28-diglycolate; betulin-3,28-diphthalate; betulin-3,28-di-L-phenylalanine; betulin-di-L-valine; betulin-28-succinate; betulin-3,28-disuccinate; betulin-3,28-di-(polyethylene glycol)-COOH (Mw=906 pure); betulinic acid; betulon-1-ene-2-ol; betulin-3,28-(dipoly(ethylene glycol)bis (carboxymethylester); hederin hydrate; lupeol-3-glutarate; lupeol-3-succinate; lupeol-3-thiodiglycolate; lupeol-3-phthalate; oleanolic acid; or uvaol.
Another specific group of compounds of formula (I) is betulin-3-caffeate; betulin-28-diglycolate; betulin-3,28-diglutarate; betulin-3,28-diglycine; betulin-3,28-didiglycolate; betulin-3,28-dimaleate; betulin-3,28-diphosphate; betulin-3,28-diphthalate; betulin-3,28-di-L-valine; lupeol; lupeol-3-amine; lupeol-3-(3xe2x80x2,3xe2x80x2-dimethyl)succinate; lupeol-3-maleate; lupeol-3-phosphate; lupeol-3-thiodiglycolate; lupenone; lupenon-1,2-ene-2-ol; or lupenon-3-oxime.
A specific group of compounds of formula (II) is 3-xcex2-acetoxy-19xcex1H-19,28 lactone oleanan; allobetulin; allobetulin-3-succinate; allobetulin-3-glycine ester; allobetulin lactone; allobetulin lactone-3-acetate; allobetulin lactone-3-phosphate; allobetulin-3-L-alanine; allobetulin-3-L-valine; allobetulin-3-L-proline; allobetulin-3-succinate; allobetulin-3-diglycolate; allobetulin-3-glutarate; allobetulin-3-phthalate; allobetulin-3-methylenamine; allobetulin-3-ethanolamine; allobetulin-3-ethanolamine hydrochloride; allobetulin-3-glycolate; allobetulin-3-glutarate; allobetulin-28-glutarate; allobetulin-3-methylamine HCl; allobetulin-3-phosphate; allobetulin-3-(polyethylene glycol)-COOH (Mw=674); allobetulon; allobetulon lactone-1-ene-2-ol; allobetulon lactone-1-en-2-succinate; allobetulon-1-ene-2-ol; allobetulon-1-ene-2-diglycolate; 3-allobetulon-1-ene-2-succinate; or 3-allobetulon-1-ene-2-diglycolate.
Another specific group of compounds of formula (II) are 3-xcex2-acetoxy-19xcex1H-19,28 lactone oleanan; allobetulin; allobetulin-3-glycine ester; allobetulin lactone-3-phosphate; allobetulin-3-succinate; allobetulin-3-ethanolamine; allobetulin-3-glutarate; allobetulin-28-glutarate; allobetulin-3-methylamine HCl; allobetulin-3-phosphate; allobetulon; allobetulon lactone-1-ene-2-ol; 3-allobetulon-1-ene-2-succinate; or ursolic acid.
A specific method of the invention is the method of treating a mammal afflicted with a bacterial infection comprising administering to the mammal an effective anti-bacterial amount of a compound of formula (I) or formula (II), wherein the bacterial infection is caused by Escherichia coli, Staphylococcus sp., Enterococcus faecalis, or a combination thereof.
Another specific method of the invention is the method of treating a mammal afflicted with a bacterial infection comprising administering to the mammal an effective anti-bacterial amount of a compound of formula (I) or formula (II), wherein the bacterial infection is caused by Staphylococcus aureus. 
Another specific method of the invention is the method of inhibiting or killing a bacterium or bacteria comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (I) or formula (II), wherein the bacterium is Escherichia coli, Staphylococcus sp., Enterococcus faecalis, or a combination thereof.
Another specific method of the invention is the method of inhibiting or killing a bacterium or bacteria comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (I) or formula (II) wherein the bacterium is Staphylococcus aureus. 
Another specific method of the invention is the method of inhibiting or killing a bacterium or bacteria comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (I) wherein the contacting is in vivo.
Another specific method of the invention is the method of inhibiting or killing a bacterium or bacteria comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (I) wherein the contacting is in vitro.
Another specific method of the invention is the method of inhibiting or killing a bacterium or bacteria comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (II) wherein the contacting is in vivo.
Another specific method of the invention is the method of inhibiting or killing a bacterium or bacteria comprising contacting the bacterium with an effective antibacterial amount of a triterpene of formula (II) wherein the contacting is in vitro.
Specific triterpenes of formula (I) having antibacterial activity are shown below in Table 1 below.
Processes for preparing compounds of formula (I) and formula (II) are provided as further embodiments of the invention and are illustrated by the following procedures in which the meanings of the generic radicals are as given above unless otherwise qualified. Specifically, the compounds of formula (I) or formula (II) can be prepared from convenient starting materials, employing procedures (e.g., reagents and reaction conditions) known to those of skill in the art. For example, suitable reagents and reaction conditions are disclosed, e.g., in Advanced Organic Chemistry, Part B: Reactions and Synthesis, Second Edition, Carey and Sundberg (1983); Advanced Organic Chemistry, Reactions, Mechanisms, and Structure, Second Edition, March (1977); Greene, T. W.; Wutz, P. G. M. Protecting Groups In Organic Synthesis, Second Edition, 1991, New York, John Wiley and sons, Inc.; and Comprehensive Organic Transformations, Second Edition, Larock (1999). Additionally, specific exemplary procedures are shown in the examples herein below.
In cases where compounds are sufficiently basic or acidic to form stable nontoxic acid or base salts, administration of the compounds as salts may be appropriate. Examples of pharmaceutically acceptable salts are organic acid addition salts formed with acids which form a physiological acceptable anion, for example, tosylate, methanesulfonate, acetate, citrate, malonate, tartarate, succinate, benzoate, ascorbate, xcex1-ketoglutarate, and xcex1-glycerophosphate. Suitable inorganic salts may also be formed, including hydrochloride, sulfate, nitrate, bicarbonate, and carbonate salts.
Pharmaceutically acceptable salts may be obtained using standard procedures well known in the art, for example by reacting a sufficiently basic compound such as an amine with a suitable acid affording a physiologically acceptable anion. Alkali metal (for example, sodium, potassium or lithium) or alkaline earth metal (for example calcium) salts of carboxylic acids can also be made.
The compounds of formula I or II can be formulated as pharmaceutical compositions and administered to a mammalian host, such as a human patient in a variety of forms adapted to the chosen route of administration, i.e., orally or parenterally, by intravenous, intramuscular, topical or subcutaneous routes.
Thus, the present compounds may be systemically administered, e.g., orally, in combination with a pharmaceutically acceptable vehicle such as an inert diluent or an assimilable edible carrier. They may be enclosed in hard or soft shell gelatin capsules, may be compressed into tablets, or may be incorporated directly with the food of the patient""s diet. For oral therapeutic administration, the active compound may be combined with one or more excipients and used in the form of ingestible tablets, buccal tablets, troches, capsules, elixirs, suspensions, syrups, wafers, and the like. Such compositions and preparations should contain at least 0.1% of active compound. The percentage of the compositions and preparations may, of course, be varied and may conveniently be between about 2 to about 60% of the weight of a given unit dosage form. The amount of active compound in such therapeutically useful compositions is such that an effective dosage level will be obtained.
The tablets, troches, pills, capsules, and the like may also contain the following: binders such as gum tragacanth, acacia, corn starch or gelatin; excipients such as dicalcium phosphate; a disintegrating agent such as corn starch, potato starch, alginic acid and the like; a lubricant such as magnesium stearate; and a sweetening agent such as sucrose, fructose, lactose or aspartame or a flavoring agent such as peppermint, oil of wintergreen, or cherry flavoring may be added. When the unit dosage form is a capsule, it may contain, in addition to materials of the above type, a liquid carrier, such as a vegetable oil or a polyethylene glycol. Various other materials may be present as coatings or to otherwise modify the physical form of the solid unit dosage form. For instance, tablets, pills, or capsules may be coated with gelatin, wax, shellac or sugar and the like. A syrup or elixir may contain the active compound, sucrose or fructose as a sweetening agent, methyl and propylparabens as preservatives, a dye and flavoring such as cherry or orange flavor. Of course, any material used in preparing any unit dosage form should be pharmaceutically acceptable and substantially non-toxic in the amounts employed. In addition, the active compound may be incorporated into sustained-release preparations and devices.
The active compound may also be administered intravenously or intraperitoneally by infusion or injection. Solutions of the active compound or its salts can be prepared in water, optionally mixed with a nontoxic surfactant. Dispersions can also be prepared in glycerol, liquid polyethylene glycols, triacetin, and mixtures thereof and in oils. Under ordinary conditions of storage and use, these preparations contain a preservative to prevent the growth of microorganisms.
The pharmaceutical dosage forms suitable for injection or infusion can include sterile aqueous solutions or dispersions or sterile powders comprising the active ingredient which are adapted for the extemporaneous preparation of sterile injectable or infusible solutions or dispersions, optionally encapsulated in liposomes. In all cases, the ultimate dosage form should be sterile, fluid and stable under the conditions of manufacture and storage. The liquid carrier or vehicle can be a solvent or liquid dispersion medium comprising, for example, water, ethanol, a polyol (for example, glycerol, propylene glycol, liquid polyethylene glycols, and the like), vegetable oils, nontoxic glyceryl esters, and suitable mixtures thereof. The proper fluidity can be maintained, for example, by the formation of liposomes, by the maintenance of the required particle size in the case of dispersions or by the use of surfactants. The prevention of the action of microorganisms can be brought about by various antibacterial and antifungal agents, for example, parabens, chlorobutanol, phenol, sorbic acid, thimerosal, and the like. In many cases, it will be preferable to include isotonic agents, for example, sugars, buffers or sodium chloride. Prolonged absorption of the injectable compositions can be brought about by the use in the compositions of agents delaying absorption, for example, aluminum monostearate and gelatin.
Sterile injectable solutions are prepared by incorporating the active compound in the required amount in the appropriate solvent with various of the other ingredients enumerated above, as required, followed by filter sterilization. In the case of sterile powders for the preparation of sterile injectable solutions, the preferred methods of preparation are vacuum drying and the freeze drying techniques, which yield a powder of the active ingredient plus any additional desired ingredient present in the previously sterile-filtered solutions.
For topical administration, the present compounds may be applied in pure form, i.e., when they are liquids. However, it will generally be desirable to administer them to the skin as compositions or formulations, in combination with a dermatologically acceptable carrier, which may be a solid or a liquid.
Useful solid carriers include finely divided solids such as talc, clay, microcrystalline cellulose, silica, alumina and the like. Useful liquid carriers include water, alcohols or glycols or water-alcohol/glycol blends, in which the present compounds can be dissolved or dispersed at effective levels, optionally with the aid of non-toxic surfactants. Adjuvants such as fragrances and additional antimicrobial agents can be added to optimize the properties for a given use. The resultant liquid compositions can be applied from absorbent pads, used to impregnate bandages and other dressings, or sprayed onto the affected area using pump-type or aerosol sprayers.
Thickeners such as synthetic polymers, fatty acids, fatty acid salts and esters, fatty alcohols, modified celluloses or modified mineral materials can also be employed with liquid carriers to form spreadable pastes, gels, ointments, soaps, and the like, for application directly to the skin of the user.
Examples of useful dermatological compositions which can be used to deliver the compounds of formula I or II to the skin are known to the art; for example, see Jacquet et al. (U.S. Pat. No. 4,608,392), Geria (U.S. Pat. No. 4,992,478), Smith et al. (U.S. Pat. No. 4,559,157) and Wortzman (U.S. Pat. No. 4,820,508).
Useful dosages of the compounds of formula I or II can be determined by comparing their in vitro activity, and in vivo activity in animal models. Methods for the extrapolation of effective dosages in mice, and other animals, to humans are known to the art; for example, see U.S. Pat. No. 4,938,949.
Generally, the concentration of the compound(s) of formula I or II in a liquid composition, such as a lotion, will be from about 0.1-25 wt-%, preferably from about 0.5-10 wt-%. The concentration in a semi-solid or solid composition such as a gel or a powder will be about 0.1-5 wt-%, preferably about 0.5-2.5 wt-%.
The amount of the compound, or an active salt or derivative thereof, required for use in treatment will vary not only with the particular salt selected but also with the route of administration, the nature of the condition being treated and the age and condition of the patient and will be ultimately at the discretion of the attendant physician or clinician.
In general, however, a suitable dose will be in the range of from about 0.5 to about 100 mg/kg, e.g., from about 10 to about 75 mg/kg of body weight per day, such as 3 to about 50 mg per kilogram body weight of the recipient per day, preferably in the range of 6 to 90 mg/kg/day, most preferably in the range of 15 to 60 mg/kg/day.
The compound is conveniently administered in unit dosage form; for example, containing 5 to 1000 mg, conveniently 10 to 750 mg, most conveniently, 50 to 500 mg of active ingredient per unit dosage form.
Ideally, the active ingredient should be administered to achieve peak plasma concentrations of the active compound of from about 0.5 to about 75 xcexcM, preferably, about 1 to 50 xcexcM, most preferably, about 2 to about 30 xcexcM. This may be achieved, for example, by the intravenous injection of a 0.05 to 5% solution of the active ingredient, optionally in saline, or orally administered as a bolus containing about 1-100 mg of the active ingredient. Desirable blood levels may be maintained by continuous infusion to provide about 0.01-5.0 mg/kg/hr or by intermittent infusions containing about 0.4-15 mg/kg of the active ingredient(s).
The desired dose may conveniently be presented in a single dose or as divided doses administered at appropriate intervals, for example, as two, three, four or more sub-doses per day. The sub-dose itself may be further divided, e.g., into a number of discrete loosely spaced administrations; such as multiple inhalations from an insufflator or by application of a plurality of drops into the eye.
The ability of a compound of the invention to act as an antibacterial agent may be determined using pharmacological models which are well known to the art, including the tests described in the Examples below.
The compounds of the invention may be also be useful as pharmacological tools for the further investigation of the mechanism of their antibacterial action.
The compounds of the invention can also be administered in combination with other therapeutic agents that are effective to treat bacterial infections, or to inhibit or kill a bacteria.
The system used to name the compounds of the invention will be clear to one of skill in the art based on the following examples. Names generally consist of the base structure, e.g., betulin, allobetulin, or lupeol, followed by a substituent. For example, betulin-28-succinate, with the structure shown in Example 1, consists of a succinic acid molecule esterified to the hydroxyl at carbon 28 of betulin. If no number is given for the substituent, the substitent is attached to the hydroxyl at carbon 3 on the base structure.
Betulin-3-glycerol oxalate is a compound of formula (I), wherein R4 and R5 together are hydroxyl, R2 and R3 together are xe2x80x94OC(xe2x95x90O)C(xe2x95x90O)OCH2CH(OH)CH2OH, and R1 is hydrogen. Betulin-1-ene-2-ol is a compound of formula (I), wherein the bond between carbons 1 and 2 is a double bond, R1 is hydroxyl, R2 and R3 together are hydroxymethyl, and R4 and R5 together are oxo. Uvaol is a compound of formula (II), wherein R10 is methyl, R9 is hydrogen, R8 is methyl, R7 is hydrogen, R11 is hydroxymethyl, R6 is absent and the bond between carbons 12 and 13 is double, R3 is hydrogen, R4 and R5 are methyl, R2 is hydrogen, and R1 is hydroxy. Oleanolic acid has the same structure as uvaol, except it has a carboxy at R11 instead of hydroxymethyl. The structure of hederin hydrate is disclosed at page 871 of the Aldrich Chemical Co. 2000-2001 catalog. The structure of other named compounds can be found in standard sources such as the Merck Index. xe2x80x9cBetulin arabinose galactanxe2x80x9d refers to betulin in a solution of arabino-galactan.
Unless otherwise stated, amino acid substituents are attached to the compounds of the invention through their carboxyl groups via ester linkages. Thus, betulin-3,28-diglycine is the same compound as betulin-3,28-diglycine ester.
The invention will now be illustrated by the following non-limiting Examples.